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VariantAndTelemetryDemo

README.md

Evaluation Data to Application Insights

This sample shows how to send evaluation data to Application Insights. Evaluation data occurs each time a feature result is determined by the Feature Manager.

Quickstart

To run this sample, follow these steps:

  1. Set the project as the startup project.
  2. Run the project.
  3. Check the Output tab for Application Insights Telemetry.

Example Output:

Application Insights Telemetry: {"name":"AppEvents","time":"2023-11-07T19:14:54.3549353Z","tags":{"ai.application.ver":"1.0.0.0"},"data":{"baseType":"EventData","baseData":{"ver":2,"name":"Vote","properties":{"AspNetCoreEnvironment":"Development","DeveloperMode":"true"},"measurements":{"ImageRating":3}}}}
Application Insights Telemetry: {"name":"AppEvents","time":"2023-11-07T19:14:54.4143414Z","tags":{"ai.application.ver":"1.0.0.0"},"data":{"baseType":"EventData","baseData":{"ver":2,"name":"FeatureEvaluation","properties":{"Label":"A Label","Etag":"An etag","AspNetCoreEnvironment":"Development","DeveloperMode":"true","Variant":"WithColor","FeatureName":"ImageRating","Tags.A":"Tag A value","IsEnabled":"True"}}}}

These logs show what would be emitted to a connected Application Insights resource, even if one is not yet connected.

Connecting to Application Insights

To flow these events to Application Insights, setup a new Application Insights resource in Azure. Once setup, from Overview copy the Connection String and place it in appsettings.json at ApplicationInsights > ConnectionString. After restarting the app, events should now flow to Application Insights. This document provides more details on connecting a .NET application to Application Insights.

About the App

This app uses Application Insights for ASP.NET Core. This means there is an App Insights SDK in the C# code and a separate App Insights SDK the Javascript. Lets cover what they're doing:

Javascript App Insights SDK

See Enable cliend-side telemetry for web applications

For ASP.NET, this is added to _ViewImports.cshtml

@inject Microsoft.ApplicationInsights.AspNetCore.JavaScriptSnippet JavaScriptSnippet

and then in the _Layout.cshtml <head>:

@Html.Raw(JavaScriptSnippet.FullScript)

The Javascript SDK will collect telemetry from the browser and send it to the Application Insights resource. Some examples are Page Views and Browser Timings. The Javascript SDK also automatically generates useful cookies like:

  1. ai_user - a unique user id
  2. ai_session - a unique session id

These cookies are used to correlate telemetry from the browser with telemetry from the server. The ASP.NET Application Insights SDK will detect these cookies and append them to telemetry it sends.

The Javascript SDK is not required, but is useful for collecting browser telemetry and generating these cookies out of the box.

Targeting Id

In order to connect evaluation events with other metrics from the user, a targeting id needs to be emitted. This can be done multiple ways, but the recommended way is to define a telemetry initializer. This initializer allows the app to modify all telemetry going to Application Insights before it's sent.

This example uses the provided TargetingHttpContextMiddleware and TargetingTelemetryInitializer. The middleware adds TargetingId (using the targeting context accessor) to the HTTP Context as a request comes in. The initializer checks for the TargetingId on the HTTP Context, and if it exists, adds TargetingId to all outgoing Application Insights Telemetry.

Sample App Usage

Sample steps to try out the app:

  1. Run the app. When the app is first started a User Id and Session Id will be generated. The username cookie will be set to a random integer, and the ai_user and ai_session cookies will be expired.
  2. When the page is loaded, the "ImageRating" feature is evaluated which defines three variants. Events can be seen in the Output window. (There may be a small delay as events are batched)
  3. Select a rating for the loaded image and click vote. A "Vote" event will be emitted.
  4. Go to Checkout and click "Check Out", which emits a custom event and a custom metric. This event and metric will be shown in the logs as well.
  5. If connected to Application Insights, head to the resource in the portal. Events and metrics will be there as well.
    1. Try going to Logs > New Query and run the query "customEvents". This should show the custom events emitted.
    2. Try going to Metrics. Under Metric find Custom > checkoutAmount. Change the time range to a small period of time that encompasses your events for a clearer graph.
    3. From the Metrics window, out-of-the-box metrics like Page Views and Server Requests can be viewed.